Ventilation system for inflatable pressure garments

ABSTRACT

An improved ventilation system for a space suit or other inflatable pressure garment assembly, such as used by astronauts and by pilots of high altitude vehicles operating in an environment having low oxygen content and low atmospheric pressures in which the life support gas enters at the helmet and through ducts at the extremities of the arms and exits from the garment only through ducts located at the legs after passing over the entire body of the wearer.

[ 1 June 6,1972

[54] VENTILATION SYSTEM FOR INFLATABLE PRESSURE GARMENTS Inventor:Leonard F. p Dover, Del 3,293,659 12/1966 Shepard.......,.................128/1427 X lLC Industries, Inc., Dover, Del.

May 8, 1967 Primary Examiner-Richard C. Pinkham Assistant Examiner-PaulE. Shapiro [73] Assignee:

[22] Filed:

Attorney--H. Gordon Dyke and Michael A. Sileo, Jr.

[21] Appl. No.:

An improved ventilation system for a space suit or other inflatablepressure garment assembly, such as used by astronauts 128/142,1422-1427,

54 m "8 81 7 A mm 8/ 7 1b 2 56 2 A 4" 1 8 2 J [52] US. [51] Int. [58]Field ofSearch...........................

and by pilots of high altitude vehicles operating in an environmenthaving low oxygen content and low atmospheric pres- R f Cted sures inwhich the life support gas enters at the helmet and e erences I throughducts at the extremities of the arms and exits from the garment onlythrough ducts located at the legs after passing over the entire body ofthe wearer.

UNITED STATES PATENTS 2,404,207 Akerman 128/142 5 2,861,568 Quilter eta1.......................,128/1423 7 Claims, 12 Drawing FiguresPATENTEDJuu 61972 3,667,469 SHEET 1 BF 4 '3 g; 48 iv 1/ I r 52 WI yaw MINVENTOR LEONARD F SHEPARD ATTORNEY PATENTEDJUN 6 m2 SHEET 3 BF 4INVENTOR LEO/YARD F SHEPARD BY V7 I ATTORNEY PATENTED Jun 6 1912 SHEEI'4 OF 4 ENVENTOR LEONARD F. SHEPARD ATTORNEY VENTILATION SYSTEM FORINFLATABLE PRESSURE GARMENTS The invention described herein was made inthe performance of work under a NASA contract and is subject to theprovisions of Section 305 of the National Aeronautics and Space Act of1958, Public Law 85568 (72 Stat. 435; 42 U.S.C. 2457).

This invention is an improved ventilation system for a pressure garmentassembly (referred hereinafter as a PGA).

My invention provides optimum availability of life support gas (whichmay be a mixture of gases) to the users head, and gives the PGA helmetimproved purging of carbon dioxide and defogging of the visor. It alsogives increased contact of the cool, dry, life support gas with theusers arms, legs and torso, thus achieving improved moisture evaporationand body cooling.

In PGAs such as this invention is applied to, the life support gasenters the PGA at an inlet and leaves at an exit (usually beingrecirculated by a pump in a continuous closed system). In my inventioninlets are locatedin the helmet of the PGA, preferably combined with adiffuser located there, and in the extremities of the arms, and exits attwo exhaust points located at the extremities of the legs of the PGA.

Some of the life support gas after passing through the helmet, flows tothe torso, while the rest after passing through the gloves, flows over.the arms to the torso. At the torso of the PGA all of the life supportgas then flows over the torso and along the legs and then exits; aportion of the gas therefore flows through the helmet (e.g'. 50 percent)and the remaining portion flows over the arms (eg 25 percent each) butall of the gas (100 percent) flows over the torso and thenproportionally over the legs (e.g. 50 percent). The exits or outletswhich preferably are located in the boots of the PGA, remove the exhaustgas from the system and maintain uniform and continuous gas flow.

In a preferred embodiment of my ventilation system I provide, interalia; intake and exhaust connectors which respectively couple and removelife support gas to and from the PGA; gas distributing ductsrespectively extending between the intake connector and the helmet andarms; and gas removing ducts respectively extending between the exhaustconnector and the extremities of the leg sections of the PGA. By thisconstruction, a sufficient quantity of life support gas is delivered tothe helmet and passes over the users head to the torso while theremaining portion of gas is proportionally passed through the arms tothe torso. All of the gas than flows through the torso section of thePGA and then proportionally flows through the legs to the gas removingducts located in the boots of the PGA.

Optimum distribution of life support gas to the wearers head is thusachieved for improved purging of carbon dioxide and visor defogging inthe PGA helmet. Increased contact of life support gas with the usersarms, torso and legs is also achieved for improved moisture evaporationand body cooling.

These and other features, objects and advantages of this invention willbe apparent from the following description, reference being made to theaccompanying drawings in which like reference numerals are utilized todesignate like parts throughout, it being understood that suchdescription and drawings are illustrative and not limitive of theinvention.

FIG. 1 is a schematic view of the ventilation system of the presentinvention with the space suit and helmet shown in phantom.

FIG. 2 is a perspective view of a preferred embodiment of a threechanneled ventilation duct.

FIG. 3 is a cross-sectional view of the right arm exhaust duct takenalong the line 3--3 of FIG. 1.

FIG. 4 is a cross-sectional view of the right leg exhaust duct takenalong the line 4-4 of FIG. 1.

FIG. 5 is a front perspective view of a preferred embodiment of thehelmet diffuser of FIG. 1 with sections cut-away to show the innerstructure of the helmet intake ducts which are connected to the helmetdiffuser.

FIGS. 6 and 7 are left and right side views respectively of the helmetdiffuser of FIG. 5.

FIG. 8 is an enlarged view of a section of the helmet diffuser of FIG. 5showing a gas deflector plate for diffusing the gas into the helmet.

FIG. 9 is a perspective view of a preferred embodiment of the gloveexhaust tube, wrist connector and Y-shaped connector of FIG. 1 withsections cut-away to show internal structure.

FIG. 10 is a cross-sectional view of the glove exhaust tube taken alongthe line 10--10 of FIG. 9.

FIG. 11 is a perspective view of a preferred embodiment of the bootexhaust pad of FIG. 1 with sections cut-away to show the internalchannel structure.

FIG. 12 is a cross-sectional view of the intake and exhaust plenumstaken along the lines 10-10 of FIG. 1.

Referring first to FIG. 1, the space suit 10 and helmet 12 in which myinvention is utilized, may be of any well known construction, such notbeing the subject of this invention, and as they are conventional theyare merely indicated here with phantom lines.

The ventilation system of this invention comprises a pair of intakeconnectors 14,16; a pair of exhaust connectors 18,20; intake and exhaustplenums 22,24; a plenum connector 23; a pair of torso intake ducts26,28; a pair of helmet intake ducts 30,32; a pair of arm intake ducts34,36; a pair of leg exhaust ducts 38,40; a helmet diffuser 42; a pairof Y-shaped ducts 44,46; a pair of wrist connectors 48,50; a pair ofglove intake tubes 52,54; and a pair of boot exhaust pads 56,58.

Intake connectors 14,16 and exhaust connectors 18,20 are flange mountedin conventional manner to the material of the front torso section of thePGA. A detailed description and showing of these connectors is notincluded since they are not a part of my invention. Intake connectors14,16 may be any well known single-inlet, guadruple-outlet connectorhaving a four way selective output manifold. Connectors of this type arecommercially available from Air-Lock, Inc. of Milford, Connecticut, andare identified as Connector Assembly No. 9179. The outlet connectors18,20 may be any well known single-inlet, double-outlet connector havingtwo way selective output. These connectors are also commerciallyavailable from Air-Lock, Inc., and are identified as Connector AssemblyNo. 9177.

In the preferred embodiment of FIG. 1 both of the upper connectors 14,16are functionally intake connectors. Only one of them is used at a time,the other being used, for example, when the wearer changes from one lifesupport system to another, or when it is desired to connect a second PGAin series through a buddy system jumper-duct.

One outlet of each of the intake connectors 14,16 is connected to theintake plenum 22; while the other three outlets are respectivelyconnected to the torso intake ducts, 26,28, helmet intake ducts 30,32and arm intake ducts 34,36. Plenum 22 also functions to couple intakegas from either intake connector to its opposite torso, helmet and armintake duct.

Functionally, both of the lower connectors 18,20 are exhaust connectors,one only being used at a time with the other included for life-supportchange-over and buddy system purposes.

Exhaust connectors 18,20 each have two outlets, one from each beingconnected to the exhaust plenum 24; while the other outlet is connectedto the leg exhaust ducts 38 and 40. Plenum 24 also functions to coupleexhaust gas from either leg exhaust duct to its opposite exhaustconnector.

Extending girthwise below each arm and along the side torso area of thePGA are the torso intake ducts 26,28, each terminating short of therear-center of the torso. Ducts 26,28 distribute cool, dry, intake gasto the middle torso area of the PGA.

The helmet intake ducts 30,32 extend upwardly from their respectiveintake connector, along the sides of the bottom edge of helmet 12,terminating at and connecting to the helmet diffuser 42. These ductscarry cool, dry, intake gas to the diffuser which in turn distributesand directs the gas into the helmet 12.

Below and coextensive with the torso intake ducts 26,28 are the armintake ducts 34,36. They extend girthwise below ducts 26,28, sweepingupwardly in a smooth curve across the back section of the PGA, along itsshoulder areas and then downwardly along the outer arm sections,respectively terminating at the wrist areas of the PGA. The Y-shapedducts 44,46 respectively connect the arm intake ducts 34,36 to the wristconnectors 46,50. Extending from approximately the knuckle area of eachPGA glove to its corresponding wrist connector 48,50 are glove intaketubes 52,54.

This completes the arm intake gas paths from the intake connectors 14,16to the gloves of the PGA.

Extending downwardly across the inner ankle area, outwardly across thearches of the wearer and upwardly along the outer ankle area are theboot exhaust pads 56,58. Such pads terminating at the upper ankle area,and preferably having a lower-front portion that extends along thebottom foot area of the PGA. Respectively connected to the upper-outerends of the boot pads 56,58 are the leg exhaust ducts 38,40 which extendupwardly along the outer leg sections, each terminating at theirrespective exhaust connector 18,20.

This completes the leg exhaust gas paths from the boots of the PGA tothe exhaust connectors 18,20.

This ventilation system has four primary intake modes of operation. Thelife support gas supplied to the PGA may be delivered (1) only to thetorso intake ducts 26,28, (2) only to the helmet diffuser 42 via thehelmet intake ducts 30,32, (3) only to the hand intake tubes 52,54 viathe arm intake ducts 34,36, or (4) proportionally to any two or more ofthe above mentioned helmet diffuser, glove intake tubes and torso intakeducts.

Selection of either one of these intake modes of operation is done byselectively directing all or part of the life support gas to the outletsof the intake connectors 14,16 which are respectively connected to thetorso intake ducts 26,28, helmet intake ducts 30,32, and arm intakeducts 34,36. Intake gas selectivity is provided by the above mentionedsingle-inlet, quadrupleoutlet connector. For life-support change-overand buddy system purposes, it is preferable that the outlets of theintake connectors 14,16 which are connected to the intake plenum 22 arealways open during each intake mode of operation. This feature alsoprovides balanced gas distribution to the system and a uniform pressureprofile.

There is only one primary exhaust mode of operation, to wit, the lifesupport gas may be exhausted only by the boot exhaust pads 54,56.

In FIG. 1 the unfilled-in arrows represent gas flow direction and pathsof the lifesupport gas while the filledin arrows represent gas flowdirection and paths of the exhaust gas.

The function of the cool, dry gas distributed by the torso intake ducts26,28, helmet diffuser 42 and glove intake tubes 52,54 are three fold.First they remove moisture from the PGA and cool the users body; secondthey purge the PGA, particularly in the helmet section, of carbondioxide exhaled by the user; and third they defog the face plate of thePGA helmet.

Continuous and uniform gas flow through the PGA is maintained by keepingthe pressure at the lower ends of the legs lower than the pressure valueof the intake gas to the system. In the embodiment shown and describedhere this is achieved by connecting life-support gas to the intakeconnectors 14,16 that has a higher pressure value than the pressurevalue at the exhaust connectors 18,20.

The pressure differential (AP) between intake (P,) and exhaust (P,,) maybe computed as follows:

1. Determine the quantity of gas necessary to adequately ventilate andpurge the space suit in which this ventilation system is to be used withminimum-user-comfort" as a guide, this quantity may be either in lbs/hror CFM/min depending, for convenience, on whether absolute pressure is avariable;

2. Compute the differential pressure (AP required to compensate forpressure losses in each of the suit and system components (AP ;AP,;APetc.).

A first approximation of a formula for the required pressure difference(AP between intake (P and exhaust (P would be P P -APflAPg +AP3 etc.EAPMGI Reference is now made to FIGS. 2-4 which respectively show: l) aperspective view of the arm intake duct 34, which is a three coil gasduct; (2) a cross-sectional view of the arm intake duct 34; and (3) across-sectional view of the leg exhaust duct 38, which is a four coilgas duct. The elements in FIGS. 3 and 4 are slightly separated from eachother for graphic representation simplification.

To significantly reduce pressure loses in the ventilation system of anypressurized space suit, substantially constant cross-section ornon-crushable gas carrying ducts should be used. FIGS. 2-4 showpreferred embodiments of ducts having substantially constantcross-section or non-crushable characteristics. A more detaileddescription of non-crushable conduits may be found in a co-pendingpatent application, Ser. No. 782,283, filed Dec. 9, 1968, which isassigned to the assignee of this patent application.

The helmet intake duct 34 of FIGS. 2 and 3 comprises coil members60,62,64, inner covers 66,68 and outer covers 70,72. The coils 60,62,64are made of hard material, such as wire or plastic, and have spacedparallel axes. Surrounding the coils and holding them in relativeposition are the inner covers 66,68, such being connected together bytwo rows of longitudinal stitching 74,76. Positioned about the innercovers 66,68 are the outer covers 70,72, such being secured at theirareas of overlap by adhesive 78. Gas duct 34 is connected to the PGA 10by adhesive 80.

Inner covers 66,68 need not be impermeable to the gas passing throughthe duct, but outer covers 70,72 must be substantially impermeable tosuch gas so that the required volume of gas may be coupled to the helmetsection of the PGA with a minimum of gas leakage. Preferably, innercovers 66,68 are made from nylon mesh fabric, while the outer covers70,72 are made from a sheet of rubber coated nylon fabric.

It is to be understood that inner covers 66,68 and outer covers 70,72may be sleeves rather than the preferred two piece construction shownand described. The longitudinal stitchings 74,76, however are still usedto hold and orientate the coils whether the two piece construction orthe sleeve construction is used.

The above described two piece inner and outer cover construction isdesirable because it (1) simplifies fabrication techniques, (2) allowsproduction line compensation for slight variations in materialdimensions and stitch characteristics, and (3) permits more accurateinspection of materials during fabrication.

Since the four coil, leg exhaust duct 38 of FIG. 4 is structurallysimilar in many respects to the three coil arm intake duct 34 of FIG. 3,like elements thereof are referenced with numerals identical to theircorresponding elements in the three coil duct 34.

The primary differences between the ducts 34 and 38 are 1) the additionof coil 65, (2) the inner covers 66 and 68 are wider to compensate forthe extra coil 65, and (3) the exhaust duct 38 is secured to the PGA 10by a fabric strip connector 79, which overlays the top and sides of theexhaust duct 38 and has its ends secured to the PGA 10 by adhesive 80.

It is contemplated that other well known techniques can be used tosecure the intake and exhaust ducts of the system to the PGA, e.g., theycan be stitched or heat sealed, without departing from the scope of thisinvention.

The above described three coil and four coil gas ducts areinterchangeable in the system in that each may be used as either intakeor exhaust ducts. In the preferred embodiment of this invention thetorso intake ducts 26,28, helmet intake ducts 30,32 and arm intake ducts34,36 are three coil ducts, while the leg exhaust ducts 38,40 are fourcoil ducts.

Although the torso intake ducts 26,28 are substantially the same as thethree coil ducts above described, they are also capable of uniformlydiffusing intake gases to the torso section of the PGA when desired.This feature may be provided by making the outer covers 70,72 of theducts gas permeable. One technique is to perorate the outer covers 70,72in spaced intervals. Of course, other well known techniques forproviding this gas permeable feature may be used.

FIGS. 5-8 respectively show: l a front perspective view of the helmetdiffuser 42 and the helmet intake ducts 30,32 with cut-away portions toshow how the ducts are joined; (2) a left side view of the diffuser 42showing the open end of the intake gas channel and the spaced diffuserplates; (3) a right side view of the diffuser 42 showing the closed endof the intake gas channel and the spaced diffuser plates; and (4) anenlarged view of a single diffuser plate with cut-away portions.

Diffuser 42 has an outer surface that conforms to and abuts the innersurface of the helmet section 12, and an inner surface that conforms tothe rear of the head of the user. The lower end of the diffuser 42 issecured to the inner neck ring 82 of a conventional PGA neck ringconnector. Secured to the inner neck ring 82 is outer neck ring 84,which is also secured to the PGA 10. The primary reason for neck rings82,84 is to provide a detachable helmet feature. That is to say, neckrings 82,84 should be detachably secured to each other so that thehelmet 12 can be disconnected and taken off when desired. Helmetdisconnect structure is not shown or described here since it is not apart of may invention.

Formed in the helmet diffuser 42 is a channel 86 extending from thelower left edge, up the left side across the top and down the rightside, terminating short of the lower right edge. Channel 86 forms afront ridge 88 and a rear surface 90.

At spaced intervals along the front ridge 88 are diffuser plates 92.Plates 92 are seated in spaced slots, as shown in FIG. 8, and are eitherheld in position by friction or by an adhesive.

When diffuser 42 is secured to the helmet 12, rear surface 90 and theupper edges of diffuser plates 92 abut the inner surface of the helmet12. By this construction (1) a primary airflow duct is formed in thehelmet diffuser 42, as defined by the channel 86 and the overlying areaof the inner surface of the helmet 12, and (2) a plurality of adjacentoutlets are provided from the air-flow duct, each defined by any twoadjacent diffuser plates 92, the front ridge 88 and the overlying areaof the inner surface of the helmet 12.

Intake ducts 30,32 are joined together and secured to the inner neckring 82 for coupling life support gas to the helmet diffuser 42. Apreferred construction for joining the intake ducts 30,32 is shown atthe bottom of FIG. 5.

The lower coil of the intake ducts 30,32 are joined together, but theupper two coils of each intake duct are positioned in parallelism toform a four coil duct 94 as shown in FIG. 4. The upper end of duct 94 isconnected to the inner neck ring 82 by a neck ring connector 96, whichhas a slot 98 formed therein. Neck ring connector slot 98 is directlybelow and corresponds to an inner ring slot 100, which in turn isdirectly below and corresponds to the channel 86 of the helmet diffuser42.

Positioned below the upper coils of intake ducts 30,32 and above thejoined" lower coils is a triangular-shaped spacer 102. This spacer holdsthe upwardly bending upper coils of ducts 30,32 in the position shown.They may be made of relatively stiff air permeable material such as anylon mesh corrugated fabric.

The intake gases are therefore coupled to the helmet 12 via helmetintake ducts 30,32, for coil duct 94, neck ring connector slot 98, innerneck ring slot 100, and channel 86. The above mentioned primary air-flowduct defined by channel 86 then couples the life support gas to each ofthe above mentioned adjacent outlets defined by the diffuser plates 88which in turn uniformly distribute and diffuse the intake gas into thehelmet 12.

It is to be understood at this point that other well known life supportgas distribution and diffusing techniques may be substituted withoutdeparting from the spirit and scope of this invention.

FIGS. 9 and 10 respectively show (1) a perspective view of a structurefor coupling life support gas to the glove sections of the PGA, and (2)a crosssectional view of the glove intake tube 52. In FIG. 9 parts ofthe arm intake duct 34, Y connector 44, wrist ring 48 and glove intaketube 52 are cut away to show preferred internal structure, while in FIG.10 the ele ments of the glove intake tube 52 are slightly separated fromeach other for graphic representation simplification.

Glove intake tube 52 extends from the upper knuckle area of the user tohis wrist and includes spacer coils 104,106, corrugated spacer 108,inner cover 110, outer cover 112, and glove intake tube connector 1 14(partially cut away). The longitudinal axis of spacer coils 104,106 andspacer 108 are preferably parallel with the spacer coils 104,106 beingmade of hard material, such as wire or plastic, and the spacer 108 beingmade of a nylon mesh fabric, corrugated as shown, and held in thatposition by upper and lower transverse stitches 1 17, 1 18.

Surrounding the spacer coils 104,106 and spacer 108, and holding them inrelative position is the inner cover 110, such being connected bystitches 116. Positioned around the inner cover 110 is outer cover 112,such being secured at its area of overlap by adhesive 120. The gloveintake tube connector 1 14 secures one end of intake tube 52 to thewrist ring 48, while the other end of tube 52 is unsecured and free.

Inner cover 110 need not be impermeable to the gas passing through theintake tube, but the outer cover 1 12 is preferably gas impermeable.Inner cover 110 may be made from a nylon mesh fabric, while the outercover may be made from a sheet of rubber coated nylon fabric.

To permit gas passage from the glove intake tube 52 to the glove area ofthe PGA, the free end thereof is constructed so as to be gas permeable.This may be achieved by terminating the outer cover 112 short of the endof the intake tube 52, as shown in FIG. 9, or by using a full outercover perforated at the end to allow gas passage.

Glove intake tube 52 should be at least crush resistant and preferablyas non-crushable as the intake and exhaust ducts above described so longas the required degree of flexibility is provided in the glove areas ofthe PGA. Accordingly, any well known intake member can be substituted solong as it has crush resistance characteristics yet is slightlyflexible.

Wrist ring 48 includes upper and lower rims 120,122, connected togetherby inner and outer cylinders 123,124. A slot 126 is provided in thelower rim 122 while a corresponding slot 115 is provided in the gloveintake tube connector 114. Holes 128 are provided in the lower rim 122for securing the glove intake tube connector 114 to it. By thisconstruction, an unimpeded path for gas flow is provided from the gloveintake tube 52, through the glove intake tube connector 114 and lowerrim 124 to the space between the inner and outer cylinders 123,124.

The legs of Y-duct 44 are identical and respectively include spacercoils 60,62, and 61,64, inner covers 67,69, and outer covers 71,73.Although the legs of Y-duct 44 are shown with one piece inner and outercovers, it is to be understood that the two piece construction abovedescribed regarding the ducts of FIGS. 2 and 3 may be substituted.

Two identical Y-duct connectors 130 secure the legs of the Y-duct 44 tothe upper rim 120, with each having a slot 131 formed therein. Upper rimhas slots 129 formed therein which correspond to slots 131, andappropriate holes for securing the Y-duct connectors 130 to it. By thisconstruction, two unimpeded paths for gas flow are provided from thespace between the inner and outer cylinders 123,124, through the upperrim 120 and connectors 130 to the legs of the Y-duct 44.

The tail of the Y-duct 44 includes spacer coils 60 and 64, which are theoutside spacer coils of the arm intake duct 34, and inner spacer coil62. Spacer coil 61 terminates slightly above the junction of the legs ofthe Y-duct and is interdigitated with the inner spacer coil 62.Structurally, the tail of Y-duct 44 merges into the lower end of the armintake duct 34.

The structure of FIGS. 9 and 10 shows a preferred, partially crushresistant, partially non-crushable, unimpeded path for gas flow from thearm intake ducts to the PGA gloves.

In FIG. 1 1, a perspective view of a preferred embodiment of the bootexhaust pad 56 of FIG. 1 is shown with sections cutaway to showpreferred internal structure.

Boot exhaust pad 56 extends from the leg exhaust duct 38, along theouter ankle area, inwardly across the arches of the wearer and upwardlyalong the inner ankle area, terminating at the upper-outer ankle area.Pad 56 also has a lower-front portion that extends along the bottom footarea of the PGA.

The outer ankle section of the exhaust pad 56 comprises a corrugatedspacer 132, made of a nylon mesh fabric and held in position by upperand lower transverse stitches 134,136, and a cover 138; while the innerankle section of boot pad 56 comprises a corrugated spacer 133, alsomade of a nylon mesh fabric having upper and lower transverse stitches135,137, and a cover 139. The bottom section of pad 56 is preferably twolayers of corrugated spacers 142,143, which are identical to spacers132,133, surrounded by cover 140.

The covers 138,139 and 140 are gas permeable, thus providing a path forgas flow from the boot area of the PGA to the leg exhaust duct 38.Spaced perforations in covers 138,139, and 140 adequately provide gaspassage through the boot pad.

At the upper end of the outer ankle section of boot pad 56, the cover138 is larger as shown at 142. This larger cover portion 142 allows thespacer coils 60,62,64,65 of the leg exhaust duct 38 to overlap thecorrugated spacer 132 and connects the ends of the leg exhaust duct 38to the boot pad 56.

Since the boot exhaust pad 58 is identical to boot pad 56, except thatit is a mirror image of it, a detailed description thereof is notincluded.

The structure of FIG. 11 shows a preferredcrush resistant, unimpededpath for exhaust gas flow from the PGA boots to the leg exhaust ducts.

Referring now to FIG. 12, a cross-sectional view of the intake andexhaust plenums 22,24, and plenum connector 23 is shown. Since theintake and exhaust plenums are identical, like elements thereof havebeen referenced with the same numeral.

Each plenum comprises a plurality of coil spacers 144, inner covers146,148, rubber bladder 152, and outer cover 154. Coils 144 are made ofhard material, such as wire or plastic, and have spaced parallel axes.Surrounding the coils and holding them in relative position are theinner covers 146,148, such being connected together by longitudinal rowsof stitches 150. Positioned about the inner covers 146,148 is the rubberbladder 152 which snugly abuts them. Tightly positioned about thebladder 152 is the outer cover 154. The plenums are held in relativeposition by the plenum connector 156, which has its ends securedtogether at this area of overlap by adhesive 158, and are secured to thePGA 10 by adhesive 160.

The foregoing description sets forth a preferred embodiment of mayinvention, to wit, a ventilation system in which the life support gasenters at the helmet and lower arm sections of the PGA and the exhaustgas exits at the leg sections of the PGA. It is to be understood,however, that the life support gas may enter at the helmet and lower legsections of the PGA and the exhaust gas may exit at the lower armsections of the PGA without departing from the spirit and scope of myinvention.

While I have illustrated the presently preferred embodiment of myinvention, it will be understood that its teachings, in whole or inpart, can be incorporated in many variations.

What is claimed is:

1. A ventilating system for distributing life-support gas to andremoving exhaust gas from an inflatable pressure garment assemblywherein:

l said assembly has helmet, arm, leg and torso sections;

2. life-support gas intake and exhaust connectors are positioned in saidtorso section for respectively conveying said life-support gas to andsaid gas as exhaust from said assembly;

3. a pair of helmet intake ducts are operatively connected between saidintake connector and said helmet section for distributing at least aportion of said life-support gas into said helmet section so as to purgesaid helmet section of carbon dioxide;

4. a pair of arm intake ducts are operatively connected between saidintake connector and the lower portions of the arm sections forconveying at least a portion of said life-support gas into said lowerarm sections; and

5. a pair of leg exhaust ducts are operatively connected between saidexhaust connectors and said leg sections, for conveying gas as exhaustfrom the assembly to said exhaust connector; whereby 6.- lower pressurein the leg sections of the said assembly than the pressure value of theinput life-support gas causes said gas to flow through said helmet andarm sections to said torso section and then to proportionally flowthrough said leg sections to said leg exhaust ducts, thus providingincreased contact of said life-support gas with the user's body formoisture evaporation and body cooling.

2. The ventilating system of claim 1 in which said life-support gasintake connector has a pair of torso intake ducts operatively connectedthereto, said torso intake ducts positioned in the area of the user'storso for diffusing at least a portion of said life-supporting gasagainst the users torso.

3. The ventilation system of claim 1 in which said intake connector isadjustable so that either one or both of said helmet and arm intakeducts may be used to distribute life-support gas to said assembly sothat a variable quantity of life-support gas may be conveyed to saidhelmet section and the remaining quantity of life-support gas may beconveyed to the extremities of said arm sections.

4. The ventilation system of claim 1 in which:

1. said intake connector is adjustable so that either said helmet orsaid arm intake ducts may be used to distribute intake gas to saidassembly; and

2. said exhaust connector is adjustable so that either of said exhaustducts may be used to remove exhaust gas from said assembly.

5. A ventilating system for distributing life-support gas to andremoving exhaust gas from an inflatable pressure garment assemblywherein:

1. said assembly has helmet, arm, leg and torso sections;

2. life-support gas intake and exhaust connector means are positioned insaid torso section for respectively conveying said life-support gas toand said gas as exhaust from said assembly;

3. helmet intake duct means is operatively connected between said intakeconnector means and said helmet section for distributing at least aportion of said life-support gas into said helmet section so as to purgesaid helmet section of carbon dioxide;

4. a pair of arm intake duct means are operatively connected betweensaid intake connector means and the lower portions of the arm sectionsfor conveying at least a portion of said life-support gas into saidlower arm sections; and

5. a pair of leg exhaust duct means are operatively connected betweensaid exhaust connector means and said leg sections, for conveying gas asexhaust from the assembly to said exhaust connector; whereby 6. lowerpressure in the leg sections of the said assembly than the pressurevalue of the input life-support gas causes said gas to flow through saidhelmet and arm sections to said torso section and then to proportionallyflow through said leg sections to said leg exhaust duct means, thusproviding increased contact of said life-support gas with the users bodyfor moisture evaporation and body cooling.

6. The ventilation system of claim in which said helmet intake ductmeans includes at least one helmet intake duct having one end connectedto said gas intake connector means and its other end connected to ahelmet diffuser connected to the rear area of said helmet section, saidat least one helmet intake duct conveying at least a portion of saidlife-support gas from said intake connector means to said diffuser, andsaid diffuser diffusing said intake gas against the users head andagainst the front area of said helmet section so as to purge said helmet

1. A ventilating system for distributing life-support gas to andremoving exhaust gas from an inflatable pressure garment assemblywherein:
 1. said assembly has helmet, arm, leg and torso sections; 2.life-support gas intake and exhaust connectors are positioned in saidtorso section for respectively conveying said lifesupport gas to andsaid gas as exhaust from said assembly;
 3. a pair of helmet intake ductsare operatively connected between said intake connector and said helmetsection for distributing at least a portion of said life-support gasinto said helmet section so as to purge said helmet section of carbondioxide;
 4. a pair of arm intake ducts are operatively connected betweensaid intake connector and the lower portions of the arm sections forconveying at least a portion of said life-support gas into said lowerarm sections; and
 5. a pair of leg exhaust ducts are operativelyconnected between said exhaust connectors and said leg sections, forconveying gas as exhaust from the assembly to said exhaust connector;whereby
 6. lower pressure in the leg sections of the said assembly thanthe pressure value of the input life-support gas causes said gas to flowthrough said helmet and arm sections to said torso section and then toproportionally flow through said leg sections to said leg exhaust ducts,thus providing increased contact of said life-support gas with theuser''s body for moisture evaporation and body cooling.
 2. life-supportgas intake and exhaust connectors are positioned in said torso sectionfor respectively conveying said life-support gas to and said gas asexhaust from said assembly;
 2. The ventilating system of claim 1 inwhich said life-support gas intake connector has a pair of torso intakeducts operatively connected thereto, said torso intake ducts positionedin the area of the user''s torso for diffusing at least a portion ofsaid life-supporting Gas against the user''s torso.
 2. said exhaustconnector is adjustable so that either of said exhaust ducts may be usedto remove exhaust gas from said assembly.
 2. life-support gas intake andexhaust connector means are positioned in said torso section forrespectively conveying said life-support gas to and said gas as exhaustfrom said assembly;
 3. helmet intake duct means is operatively connectedbetween said intake connector means and said helmet section fordistributing at least a portion of said life-support gas into saidhelmet section so as to purge said helmet section of carbon dioxide; 3.The ventilation system of claim 1 in which said intake connector isadjustable so that either one or both of said helmet and arm intakeducts may be used to distribute life-support gas to said assembly sothat a variable quantity of life-support gas may be conveyed to saidhelmet section and the remaining quantity of life-support gas may beconveyed to the extremities of said arm sections.
 3. a pair of helmetintake ducts are operatively connected between said intake connector andsaid helmet section for distributing at least a portion of saidlife-support gas into said helmet section so as to purge said helmetsection of carbon dioxide;
 4. a pair of arm intake ducts are operativelyconnected between said intake connector and the lower portions of thearm sections for conveying at least a portion of said life-support gasinto said lower arm sections; and
 4. The ventilation system of claim 1in which:
 4. a pair of arm intake duct means are operatively connectedbetween said intake connector means and the lower portions of the armsections for conveying at least a portion of said life-support gas intosaid lower arm sections; and
 5. a pair of leg exhaust duct means areoperatively connected between said exhaust connector means and said legsections, for conveying gas as exhaust from the assembly to said exhaustconnector; whereby
 5. A ventilating system for distributing life-supportgas to and removing exhaust gas from an inflatable pressure garmentassembly wherein:
 5. a pair of leg exhaust ducts are operativelyconnected between said exhaust connectors and said leg sections, forconveying gas as exhaust from the assembly to said exhaust connector;whereby
 6. lower pressure in the leg sections of the said assembly thanthe pressure value of the input life-support gas causes said gas to flowthrough said helmet and arm sections to said torso section and then toproportionally flow through said leg sections to said leg exhaust ducts,thus providing increased contact of said life-support gas with theuser''s body for moisture evaporation and body cooling.
 6. lowerpressure in the leg sections of the said assembly than the pressurevalue of the input life-support gas causes said gas to flow through saidhelmet and arm sections to said torso section and then to proportionallyflow through said leg sections to said leg exhaust duct means, thusproviding increased contact of said life-support gas with the user''sbody for moisture evaporation and body cooling.
 6. The ventilationsystem of claim 5 in which said helmet intake duct means includes atleast one helmet intake duct having one end connected to said gas intakeconnector means and its other end connected to a helmet diffuserconnected to the rear area of said helmet section, said at least onehelmet intake duct conveying at least a portion of said life-support gasfrom said intake connector means to said diffuser, and said diffuserdiffusing said intake gas against the user''s head and against the frontarea of said helmet section so as to purge said helmet section of carbondioxide and defog said to be front section thereof.
 7. The ventilationsystem of claim 5 in which said intake duct means includes a helmetdiffuser connected to the rear area of said helmet section for diffusingsaid life-support gas against the user''s head and against the frontarea of said helmet section so as to purge said helmet section of carbondioxide and defog said front area.